The present invention relates to a continuous freezing apparatus utilizing a belt conveyor.
There has so far been proposed a continuous freezing apparatus as shown in FIGS. 1 and 2. In the figures, a reference numeral 1 designates a steel belt; a numeral 2 a tension pulley for imparting a tension to the steel belt 1; a numeral 3 a driving pulley for driving the steel belt 1; a numeral 4 a brine tank equipped with an injection nozzle for injecting cold brine 10 to the steel belt 1; a numeral 5 products to be frozen; a numeral 11 a flexible sheet conveyor; a numeral 13 a pair of conveyor chains to which the flexible sheet is attached; a numeral 14 a pair of sprockets for rotating the conveyor chains 13; a numeral 15 cold brine filled in the flexible sheet 12; numerals 16 designate inlets for cold brine through which the cold brine is introduced in the brine tank 4 and the flexible sheet 12; numerals 17 outlets for the cold brine; a numeral 18 designates a driving motor for the steel belt 1; 19 a chain for transmitting revolutional force of the driving motor to the driving pulley 3 for the steel belt 1 and a numeral 6 a heat-insulating tunnel surrounding the flexible sheet conveyor 11.
The operation of the conventional continuous freezing apparatus will be described.
Products 5 to be frozen are introduced through a product supplying opening 7 to be placed on the steel belt 1 and are fed to a freezing zone 9 in the heat-insulating tunnel 6. In the freezing zone 9, the products 5 to be frozen are subjected to freezing effect from the lower side through the steel belt 1 by the cold brine 10 injected from the nozzle 20 in the brine tank 4. At the same time, they are subjected to freezing effect by the cold brine 15 held in the flexible sheet conveyor 11 through the flexible sheet 12. Then, the frozen products are transferred to the next steps through an outlet 8.
The steel belt 1 is driven by the driving pulley 3 through the chain 19 which is, in turn, driven by the driving motor 18. Since the flexible sheet 12 is in contact with the steel belt 1 and the products 5 to be frozen, on the steel belt 1, the flexible sheet conveyor 11 is driven due to frictional force generated between the flexible sheet 12 carrying therein the cold brine 15 and the steel belt 1 or the products 5, on account of which a continuous rotating movement of the flexible sheet 12 is effected by the conveyor chain 13 to which the flexible sheet 12 is attached and the sprockets 14. The cold brine 10 in the brine tank 4 and the cold brine 15 in the flexible sheet 12 are supplied from the cold brine inlets 16 and are discharged through the cold brine outlets 17 to be circulated through a brine receiver installed out of the apparatus.
In the conventional flexible sheet conveyor constructed as above-mentioned, when the flexible sheet 12 is turned around the sprockets 14, a sharp wrinkle 122 is formed in the central portion 121 of the flexible sheet 12 shown in FIGS. 3 through 5 because a convex surface and a concave surface of the flexible sheet 12 reversed at the end position shown in FIG. 5 and in addition, the flexible sheet 12 is subjected to a tension due to the cold brine 15, whereby the flexible sheet 12 is worn to cause its breakage.